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Transplant Immunology Flashcards

6 cards from real CHT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 6 Transplant Immunology flashcards as text

  1. What is the 'direct pathway' of allorecognition?

    Answer: Host T cells recognize intact donor HLA-peptide complexes displayed on donor APCs

    In the direct pathway, recipient T cells recognize intact allogeneic HLA molecules (with bound peptide) directly on donor-derived APCs, driving acute rejection.

  2. Graft-versus-Host Disease (GVHD) in hematopoietic stem cell transplantation is primarily caused by which donor cells?

    Answer: Donor T lymphocytes attacking recipient tissues

    GVHD occurs when mature donor T cells in the graft recognize host alloantigens as foreign and mount an immune attack against the recipient's tissues.

  3. Which HLA matching criterion is most critical for unrelated hematopoietic stem cell transplantation (HCT) to minimize GVHD?

    Answer: 10/10 allele-level match at HLA-A, -B, -C, -DRB1, and -DQB1

    For unrelated HCT, 10/10 allele-level matching at A, B, C, DRB1, and DQB1 is the standard of care to minimize GVHD risk and improve survival.

  4. What role do regulatory T cells (Tregs) play in transplant tolerance?

    Answer: They suppress effector T cell responses to donor alloantigens, promoting graft acceptance

    Tregs (CD4+CD25+FoxP3+) suppress alloreactive effector T cells, dampen inflammatory responses, and are central to the induction and maintenance of tolerance.

  5. In kidney transplantation, which HLA mismatch is considered most detrimental to graft survival?

    Answer: HLA-DR mismatch

    HLA-DR mismatches are consistently associated with the greatest negative impact on kidney graft survival and increased sensitization risk.

  6. What is the purpose of desensitization protocols in highly sensitized transplant candidates?

    Answer: To reduce or eliminate DSA levels to enable transplantation across a positive crossmatch

    Desensitization protocols (e.g., plasmapheresis, IVIG, rituximab) aim to lower DSA titers sufficiently to convert a positive crossmatch to negative, allowing transplantation.